Oxidative Alkene Functionalizations via Selenium-π-Acid Catalysis

Catalytic oxidative functionalizations of simple, nonpolarized alkenes represent one of the lynchpin technologies in the realm of modern methodological chemical research. In this context, Lewis-acidic selenium species have experienced a steadily increasing scope of applications in catalytic oxidations of simple alkenes throughout recent years. In analogy to their metallic counterparts, such as cationic gold and platinum complexes, selenenium ions (i.e., RSe+) display an exceptional reactivity toward π-bonds, which allows for the highly chemoselective electrophilic functionalization of alkenes. This distinct reactivity profile enabled the development of a diverse array of catalytic bond-forming processes, such as allylic and vinylic aminations, inter- and intramolecular esterifications, halogenations, and etherifications. Remarkable features associated with such protocols are the high regiocontrol, the commonly mild reaction conditions, the operational simplicity by which selenium-catalyzed alkene oxidations can be conducted, and the exquisite functional group tolerance. These aspects make selenium-π-acid catalysis very attractive for late-stage oxidations of polyfunctionalized molecules, an asset that still remains to be fully explored. In this Perspective, the latest contributions to the field of selenium-π-acid catalysis are delineated and placed into context with indicatory insights gained from previous methodological, mechanistic, and theoretical studies.